Pressure transmitter for a semiconductor processing environment

ABSTRACT

Embodiments related to measuring process pressure in low-pressure semiconductor processing environments are provided. In one example, a semiconductor processing module for processing a substrate with a process gas in a vacuum chamber is provided. The example module includes a reactor positioned within the vacuum chamber for processing the substrate with the process gas and a pressure-sensitive structure operative to transmit a pressure transmission fluid pressure to a location exterior to the vacuum chamber. In this example, the pressure transmission fluid pressure varies in response to the process gas pressure within the vacuum chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority to and the benefit of, U.S. patent application Ser. No. 13/187,300 filed on Jul. 20, 2011, and entitled “PRESSURE TRANSMITTER FOR A SEMICONDUCTOR PROCESSING ENVIRONMENT,” which is hereby incorporated by reference.

BACKGROUND

Measuring process pressure in semiconductor processing tools can be challenging. For example, process gases and byproducts present in some film deposition processes may restrict gas flow in sampling ports used by some pressure measurement devices. Consequently, pressure gauges connected to such ports may make inaccurate pressure measurements, potentially leading to poor process control and substrate quality excursions.

SUMMARY

Various embodiments are disclosed herein that relate to transmitting pressure from a vacuum chamber of semiconductor processing module to an external location via a pressure transmission fluid. For example, one embodiment provides a semiconductor processing module for processing a substrate with a process gas in vacuum chamber. The example semiconductor processing module comprises a reactor positioned within the vacuum chamber for processing the substrate with the process gas. Also included in the example module is a pressure-sensitive structure operative to transmit a pressure transmission fluid pressure to a location exterior to the vacuum chamber. In this example, the pressure transmission fluid pressure varies in response to the process gas pressure within the vacuum chamber.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a cross-section of a semiconductor process module according to an embodiment of the present disclosure.

FIG. 2 schematically shows a cross-section of a pressure-sensitive structure according to an embodiment of the present disclosure.

FIG. 3 schematically shows a top view of a base plate for a reactor including a plurality of pressure-sensitive structures according an embodiment of the present disclosure.

FIG. 4 schematically shows an inside front view of a portion of a process exhaust collector including a plurality of pressure-sensitive structures according to an embodiment of the present disclosure.

FIG. 5 schematically shows an inside top view of a portion of a process feed plenum including a pressure-sensitive structure according to an embodiment of the present disclosure.

FIG. 6 shows a flowchart for a method of processing a substrate in a low pressure substrate processing environment according to an embodiment of the present disclosure.

FIG. 7 schematically shows a top view of a semiconductor processing tool including a plurality of semiconductor process modules according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Sensing pressure within a semiconductor substrate processing environment can be important for controlling the substrate processing conditions. Pressure in low-pressure substrate processing environments has long been sensed with capacitance manometers. Such devices typically include a measurement cell configured to sense pressure by sampling process gases via a small diameter tap. The measurement cell is separated from a reference cell by a thin membrane held under a radial tension. The reference cell is maintained at a known vacuum condition, typically by a getter. As a result, changes in pressure in the processing environment cause the membrane to deflect, generating electrical signals that are translated into pressure values.

However, capacitance manometers may be sensitive to fouling resulting from substrate processing. For example, film deposition processes may cause the tap to be clogged with film and/or film deposition byproducts, potentially restricting gas flow to the measurement cell. Further, the membrane may become fouled over time, potentially changing the deflection characteristics of the membrane. Such scenarios may alter the ability of a capacitance manometer to sense pressure within the processing environment accurately.

Some approaches to address these issues include locating capacitance manometers outside of the substrate processing environment, such as in a process exhaust foreline. However, relocating the capacitance manometer outside of the substrate processing environment may not provide an accurate measurement of local pressure within the processing environment. Pressure differences between the processing environment and the capacitance manometer location may be introduced by plumbing hardware, such as pressure control valves, pipe bends, and restriction orifices, located between the processing environment and the capacitance manometer. Further, because capacitance manometers determine pressure based on the reference cell vacuum level, reference cell drift that may result from degradation of the getter may also affect the accuracy of the device.

Further still, in some substrate deposition processes, even relocating the capacitance manometer outside of the substrate processing environment may not prevent the clogging and fouling issues described above. For example, in some atomic layer deposition (ALD) processes, thin layers of film are deposited by alternately adsorbing two reactants to the substrate without supplying the reactants to the substrate processing environment concurrently. By supplying each reactant separately, only deposited film layers and the surface active species of one reactant chemisorbed to those film layers are present on the substrate when the other reactant is supplied. Consequently, highly conformal films may be formed on the substrate surface, even in high aspect ratio structures.

However, the layer-by-layer nature of ALD processes may present challenges to substrate throughput during high-volume manufacturing. One approach to speeding throughput includes supplying the substrate with a quantity of reactant suitable to provide acceptable substrate coverage of surface active species in a short duration, high concentration pulse. Because some reactants used in ALD processes may have low vapor pressures, condensation within the small diameter taps used in some capacitance manometers may aggravate clogging. Further, in some of such ALD processes, reactants may be supplied in excess to provide suitable coverage of the process surface of the substrate. Consequently, comparatively large amounts of reactant may adsorb and react elsewhere, potentially within the tap of a capacitance manometer.

The disclosed embodiments relate to detecting pressure in a semiconductor processing environment via a pressure transmission fluid. For example, a semiconductor processing module is disclosed, the processing module including a pressure-sensitive structure. The pressure-sensitive structure is operative to transmit, fluidically, a pressure transmission fluid pressure to a location exterior to the vacuum chamber within suitable range of operating conditions for the example semiconductor processing module. It will be appreciated that any suitable operating conditions may be employed without departing from the scope of the present disclosure. In one non-limiting embodiment, the semiconductor processing module may be configured to process substrates in a range of temperatures between 150 Celsius and 400 Celsius and in a range of pressures between 0 and 10 Torr, both within an acceptable tolerance. Further, it will be appreciated that the semiconductor processing module may be configured to operate at a range of conditions outside of substrate processing conditions, such as during maintenance routines. In one non-limiting embodiment, the semiconductor processing module may be configured to operate at between 5 mTorr and 760 Torn

As explained in more detail below, movement of the pressure-sensitive structure causes the pressure transmission fluid, a fluid that is suitably incompressible within an acceptable tolerance at a selected temperature, to transmit process pressure information to the external location where the pressure information may be collected by a suitable sensor. It will be appreciated that process pressure information may be transmitted at any suitable level of sensitivity without departing from the present disclosure. In one non-limiting embodiment, the pressure-sensitive structure may cause transmission of pressure information accurate to within 0.075% of a measurement span over which process pressure is to be measured. For example, in a system configured to measure process pressure over a range of 0 to 77.6 Torr, process pressure changes may be detected with an accuracy of +/−0.06 Torr.

In some embodiments, the pressure-sensitive structure may comprise one or more displaceable diaphragms disposed within one or more of a process feed plenum, a reactor, and a process exhaust collector included within the vacuum chamber. In such embodiments, the displaceable diaphragms may be directly exposed to process fluids and/or may be disposed directly within the substrate processing environment. Thus, the disclosed embodiments offer the potential advantage of being able to measure pressure and/or pressure changes within the vacuum chamber of the semiconductor processing module without the potential disadvantages arising from small orifice taps, such as the potentially clogging and fouling issues discussed above. Further, because the pressure transmission fluid pressure in the disclosed embodiments is a suitably incompressible fluid, the disclosed embodiments may avoid the potential inaccuracies described above that may result from reference cell drift, and thus may offer the potential advantage of comparatively longer-term service life relative to some capacitance manometers.

FIG. 1 schematically shows a cross-section of an embodiment of a semiconductor processing module 100 for processing a substrate 102 in a low-pressure substrate processing environment formed within reactor 106. Reactor 106 is included in a vacuum chamber 108, which may assist in maintaining a selected pressure within the low-pressure substrate processing environment. However, it will be appreciated that, in some embodiments, reactor 106 may perform the function of vacuum chamber 108. Pressure within vacuum chamber 108 and reactor 106 is controlled at least in part by a pressure control device, depicted as throttle valve 110 on exhaust foreline 112 in the embodiment shown in FIG. 1. However, it will be appreciated that pressure control may also be achieved using various process gas feeds and reactor bypass lines (not shown). Accordingly, such feeds and bypass lines may also be considered pressure control devices within the scope of the present disclosure.

Reactor 106 includes a top plate 114 coupled to a bottom plate 116. As shown in FIG. 1, top plate 114 includes an inlet 118 for receiving process gas, e.g., reactive and non-reactive gases used during the substrate processing, from a process feed plenum 120 upstream of a process surface 122 of substrate 102. Bottom plate 116 includes an outlet 124 for expelling process gas to a process exhaust collector 126 downstream of substrate 102.

As shown in FIG. 1, inlet 118 and outlet 124 are arranged to direct process gas across process surface 122 of substrate 102. Process gas may flow across process surface 122 in any suitable flow arrangement, including unidirectionally or radially, without departing from the scope of the present disclosure. Dotted arrows included in FIG. 1 illustrate the path of process gas through the depicted embodiment of semiconductor processing module 100.

Substrate 102 is supported in the low-pressure substrate processing environment by susceptor 128. Susceptor 128 includes a heater 130 used to adjust a temperature of substrate 102 before, during, and/or after substrate processing. Susceptor 128 is mounted on an elevator 132 so that substrate 102 may be raised and lowered within vacuum chamber 108 to facilitate substrate transfer in and out of vacuum chamber 108 and to facilitate sealing susceptor 128 to bottom plate 116 during substrate processing.

One or more pressure-sensitive structures are also provided in the embodiments of the semiconductor processing modules described herein. Any suitable pressure-sensitive structure may be employed without departing from the present disclosure. In the embodiment shown in FIG. 1, a plurality of pressure-sensitive structures are depicted as pressure-sensitive structures 134A and 134B. A detailed description of one embodiment of a pressure-sensitive structure is provided with reference to FIG. 2 below.

Each pressure-sensitive structure shown in FIG. 1 is fluidically coupled with a respective pressure sensor (depicted as pressure sensors 136A and 136B) adapted to detect the pressure transmission fluid pressure at a location exterior to vacuum chamber 108. The pressure transmission fluid pressure detected by the pressure sensor is transmitted via a pressure transmission fluid included in a pressure transmission fluid line (depicted as pressure transmission fluid lines 138A and 138B, respectively).

Any suitable pressure transmission fluid that is incompressible within an acceptable tolerance under suitable operating conditions for semiconductor processing module 100 may be employed without departing from the scope of the present disclosure. Example pressure transmission fluids include, but are not limited to liquid inorganic substances, such as a suitable silicone oil and a suitable liquid metal such as mercury, and liquid organic substances, such as suitable aromatic compounds, napthenic compounds, and paraffinic compounds. In some embodiments, the pressure transmission fluid may include a single constituent, such as glycerine or nitrobenzene, free of contaminants within an acceptable tolerance. In some other embodiments, the pressure transmission fluid may include a blend of compounds, such as those used in suitable lubricating fluids and/or heat exchange fluids. Non-limiting example lubricating fluids may include olive oil, mineral oil, and/or linseed oil. One non-limiting example heat exchange fluid may include a blend of diphenyl oxide and biphenyl. In some embodiments where blends of compounds are provided, it will be appreciated that the relative concentrations of various constituents may be selected to adjust one or more thermodynamic properties of the pressure transmission fluid, such as thermal expansion, over a range of operating conditions.

In some embodiments, the pressure sensor may include a suitable pressure sensor diaphragm configured to couple fluidically with an opposite end of the pressure transmission fluid line from the pressure-sensitive structure (shown in FIG. 1 as pressure sensor diaphragms 140A and 140B, respectively). The pressure sensor diaphragm transmits process pressure information to the pressure sensor via movement of the pressure sensor diaphragm responsive to pressure changes in the pressure transmission fluid. In turn, the pressure sensor detects movement of the pressure sensor diaphragm and generates a suitable signal based on an extent of the movement of the pressure sensor diaphragm. In one non-limiting example, the pressure sensor may generate a voltage signal linearly proportional to an extent to which the pressure sensor diaphragm moves. In the embodiment shown in FIG. 1, pressure sensors 136A and 136B transmit signals to a pressure control subsystem 142 of a system process controller 144. Alternatively, in some embodiments, a suitable diaphragm may be included in the pressure transmission fluid line at a position opposite from the pressure-sensitive structure. In such embodiments, the pressure sensor may be configured to engage with this diaphragm to perform the pressure detection operations described above.

In the embodiment shown in FIG. 1, pressure control subsystem 142 transforms the signals received from pressure sensors 136A and 136B into pressure data. Such pressure data may be used to control pressure in reactor 106 and/or to control other aspects of semiconductor processing module 100. In some embodiments, temperature information received from a temperature sensor (not shown) may be used in combination with thermodynamic information about the pressure transmission fluid, such as thermal expansion data, when transforming the signals into pressure data. While the pressure transmission fluid is incompressible within an acceptable tolerance at a selected temperature, so that the density of the fluid does not vary in response to pressure changes, the density of the pressure transmission fluid may vary in response to temperature changes. The inclusion of thermodynamic information during signal transformation may provide some measure of compensation for thermally-induced variation in the pressure transmission fluid volume, potentially allowing operation over a comparatively larger range of operating conditions.

In some embodiments, the pressure transmission fluid line may include a purge valve (illustrated in FIG. 1 as purge valves 146A and 146B) so that the pressure transmission fluid line may be drained of and filled with the pressure transmission fluid. Such purge valves may also be used to remove gases from the pressure transmission fluid line, as the compressible nature of gases may interfere with pressure transmission.

As introduced above, a pressure-sensitive structure is exposed to process gases so that process pressure information may be transmitted to a location external to the vacuum chamber. FIG. 2 schematically shows a cross-section of an example embodiment of a pressure-sensitive structure 200 including a displaceable diaphragm 202. Displaceable diaphragm 202 is adapted to move responsive to changes in process gas pressure relative to a pressure of the pressure transmission fluid. In turn, movement of displaceable diaphragm 202 transmits a pressure wave through the pressure transmission fluid to a location external to the vacuum chamber. It will be appreciated that displaceable diaphragm 202 may be adapted to move in any suitable way. For example, in the non-limiting embodiment shown in FIG. 2, displaceable diaphragm 202 is adapted to deform or flex in response to process gas pressure changes. However, in some other non-limiting embodiments, displaceable diaphragm 202 may be adapted to slide within a suitable seal or bearing.

It will be appreciated that the displaceable diaphragm may be formed into any suitable shape; for simplicity, the example embodiments shown and described herein are generally circular. Displaceable diaphragm 202 may be formed from any material suited for use with the operating conditions at which the semiconductor processing module is used and suitably impermeable within an acceptable tolerance to the process gases and the pressure transmission fluid used therewith. Non-limiting examples include metals and low-volatility polymer materials.

As shown in FIG. 2, displaceable diaphragm 202 includes optional pleats 206 configured to enhance flexibility and/or movement. However, it will be appreciated that, in some embodiments, displaceable diaphragm 202 may include suitable stiffening structures (not shown) adapted to provide rigidity in one or more directions. FIG. 2 also shows a mounting flange 204 positioned around displaceable diaphragm 202 to facilitate securing pressure-sensitive structure 200 within the semiconductor processing module with suitable fasteners (not shown) or welds. Alternatively, in some embodiments, displaceable diaphragm 202 may be formed integrally within a portion of the hardware described herein.

The embodiment of displaceable diaphragm 202 shown in FIG. 2 has a process side 208 that is exposed to process gases. In some embodiments, process side 208 may include a suitable coating and/or surface treatment configured to enhance chemical compatibility of the displaceable diaphragm with the process gases, processing conditions, and/or operating conditions. Additionally or alternatively, in some embodiments, process side 208 may include surface textures adapted to resist film deposition and/or particle accumulation. In one scenario, a process side may have a smooth, electropolished surface configured to resist film nucleation. In another scenario, a process surface may have a roughened surface configured to prevent the formation of small particles as the displaceable diaphragm moves and/or flexes during use. Such surface textures may vary according to application and/or positioning of the displaceable diaphragm.

The embodiment of displaceable diaphragm 202 shown in FIG. 2 also has a transmission side 210 that is opposite the process side. Transmission side 210 is in contact with the pressure transmission fluid included in the pressure transmission fluid line so as to transmit process pressure information to the pressure sensor responsive to movement of the displaceable diaphragm. In some embodiments, the transmission side may include projections (not shown) configured to slide within portions of a pressure transmission fluid reservoir and/or the pressure transmission fluid line.

Because the pressure transmission fluid is suitably incompressible, displaceable diaphragm 202, the pressure transmission fluid, and the pressure sensor diaphragm form a closed hydraulic system. Consequently, movement of displaceable diaphragm 202 responsive to changes in process gas pressure transmits process pressure information to the pressure sensor in proportion to the effective areas of displaceable diaphragm 202 and the pressure sensor diaphragm. It will be appreciated that any suitable size relationship of between the effective area of displaceable diaphragm 202 and the pressure sensor diaphragm may be employed without departing from the scope of the present disclosure. For example, in some embodiments, displaceable diaphragm 202 may be sized larger than a corresponding pressure sensor diaphragm, so that a smaller movement of the displaceable diaphragm may lead to a larger movement at the pressure sensor diaphragm. This may have the potential benefit of enhancing the sensitivity of the pressure sensor to small changes in pressure.

Further, displaceable diaphragm 202 may also have any suitable size. In some non-limiting embodiments, a circularly shaped displaceable diaphragm 202 may have a diameter of 2 inches. Further still, it will be appreciated that the structural characteristics of displaceable diaphragm 202 may vary according to the thickness and/or construction material. Because comparatively thicker diaphragms may be more robust in some applications, displaceable diaphragm 202 may be sized in consideration of an area-to-thickness ratio for a selected sensitivity and construction material in some embodiments. For example, in an embodiment where displaceable diaphragm 202 flexes in response to process gas pressure changes, a larger displaceable diaphragm may be comparatively more robust than a smaller one for a given area-to-thickness ratio.

In some embodiments, the pressure-sensitive structure may include a reservoir of pressure transmission fluid positioned so that pressure transmission fluid contacts the pressure-sensitive structure. In the embodiment shown in FIG. 2, reservoir 212 is positioned adjacent transmission side 210. In some of such embodiments, reservoir 212 may be sized so that the pressure transmission fluid wets all of transmission side 210 within an acceptable tolerance. This may provide the potential benefit of providing comparatively more sensitive pressure measurements relative to embodiments where the pressure transmission fluid wets only a portion of transmission side 210 for displaceable diaphragms having the same effective area.

Alternatively, in some embodiments, reservoir 212 may be sized so the pressure transmission fluid wets only a portion of transmission side 210. For example, reservoir 212 may be sized so that the pressure transmission fluid only wets a portion of an extension projecting from transmission side 210. This may provide the potential benefit of reducing a volume of pressure transmission fluid included within the pressure transmission fluid line and/or potentially reducing a transient response time of pressure transmission via the pressure transmission fluid.

Because the pressure-sensitive structure is positioned within a vacuum environment, the portions of the pressure-sensitive structure exposed to the pressure transmission fluid are sealed to prevent loss of the pressure transmission fluid to the vacuum chamber. For example, in some embodiments, the displaceable diaphragm and the reservoir may be welded together or may be formed from a single piece of material. In some other embodiments, the displaceable diaphragm and the reservoir may be removably sealed together. For example, a deformable metal gasket held by a suitable vacuum-tight edge, such as a knife-edge disposed on each of the diaphragm and the reservoir, may be used to form a suitable seal in some embodiments. Similar approaches may be used to seal the pressure-sensitive structure to the pressure fluid transmission line. For example, in the embodiment shown in FIG. 2, pressure fluid transmission line 138 is depicted as being removably sealed to reservoir 212 via a gasket 214. In some other embodiments, the pressure transmission fluid line may be welded to the pressure-sensitive structure.

One or more pressure-sensitive structures may be positioned at any suitable location within vacuum chamber 108 to measure a pressure of process gas. For example, as shown in FIG. 1, pressure-sensitive structure 134A is exposed to the low-pressure substrate processing environment within reactor 106, and is positioned downstream of process surface 122 of substrate 102. So positioned, pressure-sensitive structure 134A may detect process pressure conditions in a reaction environment proximate to substrate 102. Consequently, pressure-sensitive structure 134A may transmit pressure information that is comparatively more reflective of the low-pressure substrate processing environment than a pressure measurement device located farther away, such as in exhaust foreline 112. Moreover, by positioning pressure-sensitive structure 134A downstream of substrate 102, potential particles shed by the movement of pressure-sensitive structure 134A may be carried toward outlet 124 by the flow of the process gas. Further, the top surface of pressure-sensitive structure 134A is depicted as being flush with a top surface of a lower shelf portion 148 of bottom plate 116 in the embodiment shown in FIG. 1. Depending on flow conditions within reactor 106, a smooth, flush position of pressure-sensitive structure 134A within bottom plate 116 may be conducive to forming and/or preserving a boundary layer above the bottom plate and above the pressure-sensitive structure. In turn, the boundary layer may prevent disturbance of small particles present on the pressure-sensitive structure and potentially prevent the back diffusion of such particles.

It will be appreciated that any suitable number of pressure-sensitive structures may be provided within the low-pressure substrate processing environment. While the example shown in FIG. 1 shows a single pressure-sensitive structure included within the low-pressure substrate processing environment, in some embodiments, a plurality of pressure-sensitive structures may be provided. For example, FIG. 3 schematically shows a top view of another example embodiment of a bottom plate 300. As shown in FIG. 3, bottom plate 300 includes a circular opening 302 adapted to receive a substrate supported by a susceptor (not shown) and an outlet 304 for exhausting process gases. Circular opening 302 is formed in lower shelf portion 306 of bottom plate 300. Lower shelf portion 306 is surrounded by a raised ledge 308 that is adapted to couple with the top plate (not shown).

As shown in the embodiment of FIG. 3, a plurality of pressure-sensitive structures 134 are positioned in downstream of circular opening 302 on lower shelf portion 306. For simplicity, the diameters of pressure-sensitive structures 134 are shown as being the same. For example, pressure-sensitive structures having equivalent effective areas may be used in some embodiments to provide redundant pressure measurement. However, it will be appreciated that, in other embodiments, bottom plate 300 may include a plurality of pressure-sensitive structures having different effective areas. For example, in some embodiments, a second pressure-sensitive structure may be provided to provide pressure measurement over a different range of pressures from a range of pressures measured by the first pressure-sensitive structure.

While the embodiments shown in FIGS. 1 and 3 and discussed herein show pressure-sensitive structures included within embodiments of bottom plates for reactor 106, it will be appreciated that one or more pressure-sensitive structures may be positioned in any suitable location within the low-pressure substrate processing environment without departing from the scope of the present disclosure. For example, in some embodiments, one or more pressure-sensitive structures may be included within top plate 114. Positioning a pressure-sensitive structure in top plate 114 above substrate 102 may provide pressure information that is potentially more highly correlated with process conditions at process surface 122 relative to locations more distant. Such pressure information may be helpful in diagnosing and addressing substrate process thickness profile non-uniformity excursions.

One or more pressure-sensitive structures may also be located outside of the low-pressure substrate processing environment. In some embodiments, another pressure-sensitive structure may be located outside of the low-pressure substrate processing environment in addition to a first pressure-sensitive structure located within the low-pressure substrate processing environment. In some other embodiments, a pressure-sensitive structure may be located outside of the low-pressure substrate processing environment in place of a pressure-sensitive structure located within the low-pressure substrate processing environment. For example, a pressure-sensitive structure may not be included within the low-pressure substrate processing environment in process conditions where the risk of potential particle generation by the pressure-sensitive structure may be undesirable.

An example of a pressure-sensitive structure positioned outside of the low pressure substrate processing environment is illustrated by the embodiment shown in FIG. 1, which depicts pressure-sensitive structure 134B positioned within process exhaust collector 126. Depending on the flow conditions within outlet 124 and process exhaust collector 126, positioning pressure-sensitive structure 134B within the process exhaust collector 126 may prevent back-diffusion of small particles generated by movement of the pressure-sensitive structure. It will be appreciated that one or more pressure-sensitive structures may be positioned within process exhaust collector 126. For example, FIG. 4 schematically shows an inside front view of a portion of another embodiment of a process exhaust collector 400 including a plurality of pressure-sensitive structures 134. However, any suitable number of pressure-sensitive structures may be included within process exhaust collector 400 without departing from the scope of the present disclosure.

In still other embodiments, one or more pressure-sensitive structures may be located upstream of the low-pressure substrate processing environment to monitor pressure within the process feed plenum. For example, the pressure of a process feed plenum may be monitored to check for a potential chemical vapor deposition (CVD) reaction that may initiate therein. CVD reactions occurring within the process feed plenum may have deleterious effects on substrate process conditions, including small particle generation and substrate process thickness profile non-uniformity effects. Such effects may be especially harmful during ALD processing, where uncontrolled CVD reactions may lead to unwanted film deposition and/or particle decoration.

In some ALD processes, CVD reactions may result from transient reactant concentration and/or reactor temperature conditions at process gas injection ports and process gas feed plenums. Some of such CVD reactions may be indicated by pressure information related to these gas phase processes. However, because ALD processes frequently employ pulsed doses of low vapor pressure process gases, potential condensation of the process gases within a capacitance manometer may make pressure measurement within the process feed plenum difficult. Because some embodiments of the disclosed pressure-sensitive structures may be directly exposable to such environments without using sampling ports or taps, the potential clogging and fouling problems that may result from condensation within sampling ports may be avoided.

FIG. 5 schematically shows an inside top view of a portion of an embodiment of an example process feed plenum 500, including a pressure-sensitive structure 134 exposed to process gas and configured to transmit process gas pressure information from process feed plenum 500 to a location external to the vacuum chamber. Transmitting process feed plenum pressure information using pressure-sensitive structure 134 may avoid the potential clogging and fouling issues associated with capacitance manometers described above. Positioning pressure-sensitive structure 134 on an inside top surface within process feed plenum 500 as shown in FIG. 5 may allow process feed plenum 500 to be mounted directly above the top plate of the reactor. In some embodiments, suitable baffles may be provided (not shown) to collect particles shed from pressure-sensitive structure 134.

It will be understood that the hardware described above may be used to measure pressure in a semiconductor processing module and, in turn, use the pressure information to process a substrate within the module. FIG. 6 shows a flow chart for an embodiment of a method 600 for processing a substrate in a low-pressure substrate processing environment of a semiconductor processing module. Method 600 may be performed by any suitable hardware and software. In some embodiments, method 600 may be performed by a system process controller comprising a data-holding subsystem comprising instructions executable by a logic subsystem to perform the processes described herein. It will be appreciated that portions of the processes described in method 600 may be omitted, reordered, and/or supplemented without departing from the scope of the present disclosure.

Method 600 comprises, at 602, supporting a substrate with a susceptor within a vacuum chamber. In some embodiments, 602 may comprise, at 604, sealing the susceptor against a bottom plate of a reactor within the vacuum chamber so that the substrate is positioned in a low-pressure substrate processing environment within the vacuum chamber.

At 606, method 600 comprises supplying a process gas to the vacuum chamber. For example, in an ALD process, the process gas may be supplied to the vacuum chamber so that a suitable coverage of surface active species derived from the process gas is generated on a process surface of the substrate. In some embodiments, 606 may comprise, at 608, supplying the process gas upstream of a process surface of the substrate so that the process gas flows across the process surface before flowing across a pressure-sensitive structure.

At 610, method 600 comprises transmitting to a location exterior to the vacuum chamber a pressure transmission fluid pressure with a pressure-sensitive structure, the pressure transmission fluid pressure varying in response to a process gas pressure within the vacuum chamber. In some embodiments, 610 may comprise, at 612, transmitting the pressure transmission fluid pressure via a movement of a displaceable diaphragm included in the pressure-sensitive structure. In such embodiments, the pressure-sensitive structure may be included in the bottom plate of the reactor and may be flush with a top surface of a lower shelf of the bottom plate so as not to disturb a flow of process gas flowing across the lower shelf within the reactor.

At 614, method 600 comprises detecting the process gas pressure via the pressure transmission fluid pressure, and at 616, adjusting a pressure control device responsive to the pressure transmission fluid pressure. For example, in some embodiments, one or more of a pressure control valve or a process gas feed flow rate may be adjusted in response to the pressure transmission fluid pressure.

FIG. 7 schematically shows a top view of an embodiment of a semiconductor processing tool 700 including a plurality of semiconductor processing modules 702. While the depicted embodiment includes two modules, it will be appreciated that any suitable number of semiconductor processing modules may be provided. For example, some processing tools may include just one module while other processing tools may include more than two modules.

FIG. 7 also shows load locks 704 for moving substrates between portions of semiconductor processing tool 700 at ambient atmospheric pressure conditions and portions of the tool that are at pressures lower than atmospheric conditions. An atmospheric transfer module 708, including an atmospheric substrate handling robot 710, moves substrates between load ports 706 and load locks 704, where a portion of the ambient pressure is removed by a vacuum source (not shown) or is restored by backfilling with a suitable gas, depending on whether substrates are being transferred into or out of the tool. Low-pressure substrate handling robot 712 moves substrates between load locks 704 and semiconductor processing modules 702 within low-pressure transfer module 714. Substrates may also be moved among the semiconductor processing modules 702 within low-pressure transfer module 714 using low-pressure substrate handling robot 712, so that sequential and/or parallel processing of substrates may be performed without exposure to air and/or without a vacuum break. Various pre-processing steps, such as pre-process cleaning steps, and post-processing steps, such as post-process cooling steps, may be performed using suitable cleaning stations and chill plates not shown in FIG. 7.

FIG. 7 also shows a user interface 720 connected to a system process controller 722. User interface 720 is adapted to receive user input to system process controller 722. User interface 720 may optionally include a display subsystem, and suitable user input devices such as keyboards, mice, control pads, and/or touch screens, for example, that are not shown in FIG. 7.

System process controller 722 is a computing system that includes a data holding subsystem 724 and a logic subsystem 726. Data-holding subsystem 724 may include one or more physical, non-transitory, devices configured to hold data and/or instructions executable by logic subsystem 726 to implement the methods and processes described herein. Logic subsystem 726 may include one or more physical devices configured to execute one or more instructions stored in data-holding subsystem 724. Logic subsystem 726 may include one or more processors that are configured to execute software instructions. For example, instructions held in data-holding subsystem 724 and executed by logic subsystem 726 may be used to perform various method described herein, and may further be used to control semiconductor processing tool 700.

For example, such instructions may control the execution of process recipes. Generally, a process recipe includes a sequential description of process parameters used to process a substrate, such parameters including time, temperature, pressure, and concentration, etc., as well as various parameters describing electrical, mechanical, and environmental aspects of the tool during substrate processing. The instructions may also control the execution of various maintenance recipes used during maintenance procedures and the like. Further, such instructions may be configured to operate various semiconductor processing tool control subsystems, such as gas control subsystems, pressure control subsystems, temperature control subsystems, electrical control subsystems, and mechanical control subsystems. Such control subsystems may receive various signals provided by sensors, relays, and controllers and make suitable adjustments in response.

FIG. 7 also shows removable computer-readable storage media 728, which may be used to store and/or transfer data and/or instructions executable to implement the methods and processes described herein. It will be appreciated that any suitable removable computer-readable storage media may be employed without departing from the scope of the present disclosure. Non-limiting examples include DVDs, CD-ROMs, floppy discs, and flash drives.

It is to be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various acts illustrated may be performed in the sequence illustrated, in other sequences, or omitted in some cases.

The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof. 

1. At a process controller of a semiconductor processing module, a method for processing a substrate in a vacuum chamber of the semiconductor processing module, the method comprising: supporting a substrate with a susceptor within the vacuum chamber; supplying a process gas to the vacuum chamber; transmitting to a pressure sensor diaphragm at a location exterior to the vacuum chamber a pressure transmission fluid pressure with a pressure-sensitive structure, the pressure transmission fluid pressure varying in response to a process gas pressure within the vacuum chamber; and using a pressure control subsystem, controlling a pressure within the vacuum chamber based on the process gas pressure determined during the step of transmitting.
 2. The method of claim 1, wherein supplying the process gas comprises supplying the process gas upstream of a process surface of the substrate so that the process gas flows across the process surface of the substrate before flowing across the pressure-sensitive structure.
 3. The method of claim 1, wherein the process gas pressure within the vacuum chamber during the step of transmitting is between 0 and 10 Torr.
 4. The method of claim 1, further comprising another pressure-sensitive structure disposed within a process feed plenum.
 5. The method of claim 1, further comprising another pressure-sensitive structure disposed within the vacuum chamber.
 6. The method of claim 1, further comprising the pressure control subsystem using temperature information and thermodynamic information about the pressure transmission fluid to determine pressure data.
 7. The method of claim 1, further comprising using a purge valve to remove gases from a pressure transmission fluid line.
 8. The method of claim 1, wherein the pressure-sensitive structure comprises a displaceable diaphragm that includes one or more stiffening structures.
 9. The method of claim 1, wherein a transmission side of a displaceable diaphragm of the pressure-sensitive structure includes projections configured to slide within portions of the pressure transmission fluid.
 10. The method of claim 1, wherein the pressure transmission fluid wets a portion of an extension projecting from a transmission side of the pressure-sensitive structure.
 11. The method of claim 1, wherein the pressure-sensitive structure is located downstream of a substrate and is flush with a surface of the susceptor.
 12. The method of claim 1, further comprising using a plurality of pressure-sensitive structures to measure pressure within the vacuum chamber, each of the plurality of pressure-sensitive structures having top surface mounted flush with a surface of the susceptor and located downstream of the substrate.
 13. The method of claim 12, wherein two or more of the plurality of pressure-sensitive structures have different effective areas.
 14. The method of claim 12, wherein two or more of the plurality of pressure-sensitive structures have the same effective areas.
 15. The method of claim 1, further comprising using another pressure-sensitive structure above the substrate to measure pressure within the vacuum chamber.
 16. The method of claim 1, further comprising adjusting one or more of a pressure control valve and a process gas feed flow rate in response to the process gas pressure measured using the pressure-sensitive structure.
 17. The method of claim 1, further comprising adjusting one or more of a pressure control valve and a process gas feed flow rate in response to the process gas pressure measured using a plurality of pressure-sensitive structures within the vacuum chamber.
 18. The method of claim 1, further comprising using a pressure-sensitive structure in a process exhaust collector. 